Luminous electrical discharge device



March 29, 1932- R. E. VOLLRATH LUMINOUS ELECTRICAL DISCHARGE DEVICEFiled July 22,

INVENTOR.

A TTORNEY.

Patented Mar. 29, 1932 PATENT2 OFFICE RICHARD E. VOLLRATH, OF PASADENA,CALIFORNIA LuMINoUs ELECTRICAL DISCHARGE DEviCE Application filed. July22,

now in extensive use, the gas pressure 1n the j l tube is usuallyadjusted to give a uniform steady glow which fills 'the tube.

I have found that electr-ical dischargesA through gases, that areconfined in a transparent container, may be altered in a striking Z3manner, when such container is lled with 4 granules or dielectric andinsulating material such as glass or quartz. L x The invention isillustrated in the accompanying drawings, wherein Fig. l shows aluminous tubular discharge ,device in side elevation, in which myinvention is embodied. y

Fig. 2. illustrates the same in vertical longitudinal section. 20 Fig. 3shows a .cross-sectional' detail through the same,-the sectionbeing-taken on the line,3-- 3 of Fig. 2.

Fi g. 4 illustrates the invention in a slightly modified form of tube'.v

Fig. 5 shows v a cross-sectional detail through the same as viewed onthe line 5 5' of Fi g. 4.

Fig. 6 illustrates another embodiment of the invention.

Fig. v7 shows a cross-sectional detail through the same as viewed on theline 7-7 of Fig. 6, and Fig. 8 illustrates another shape of tube inwhich my invention is embodied. `Referring particularly to Figs., 1, 2Aand 3 the numeral 10 designates a transparent container, which in thepresent instance lhas the form of a cylindrical glass tube, provided onthe interior thereof, near each of its opposite ends, with electrodes 11and 12 and suit-l d uated, then filled with a gas at reduced pressureand finally sealed,-the teat 17 indi- 1930. serial N6. 469,787.

able lead wires 13 and 14 whose inner ends are connected to saidelectrodes. These lead- Wires are sealed into the tubes vacuum-tight andserve to connect the electrodes with a current-supply through a suitabletransformer 15.

The tube 1() is practically filled with dielectric or insulatingmaterial in the form of granules 16.

'lhese granules or particles with which the tube is filled maybecomposed of quartz, glass, or any insulating material which is notdestroyed under the influence of the' electrcal discharge, and they maybe of any geometrical shape With either smo-oth or irregular surfaces.If glass or some other insulating ceramic material is employed, it mayhave the form of beads or of fragments obtained by crushing largerpieces of the' material. v

Colored granules maybe employed if desired to produce different effects.

One of the most advantageous materials, from a cost pointG of view, ispure quartz sand, known .as Ottawa sand, which may be obtained ina`variety of sizes with almost .spherical grains. The rounded formofthese grains is of some advantage because it al' lows the sand toreadily flow into bent tubes during the process of manufacture vand thisparticular quartz sand has low absorptive f lpower for gases. This isimportant. in case lthe gas to be employed is one of the rare gases ofatmosphere, such as neon, whose luminous properties are extremelysensitive to any gaseous impurities which might escape frominadequately-outgassed granulesduring the operation of the tube. l

The tube containing'the granules is evaceating the vpoint at which theseoperations take place.

All of these operations are well known to those familiar with themanufacture of discharge tubes and therefore form no part of the presentinvention. v

The kind of gas employed may also be Ivaried, asit is known that neongas willproduce a different colored effect `from that which helium gaswill produce so that vari- .ous colored effects may be producedaccordcharge-tube and follows an extremely crooked or zig-zag paththrough the spaces bctween the granules lying near this wall surface orin contact with it substantially as shown by zig-zag lines in Fig. 1.

I have found thatthis discharge takes place most readily when theelectrodes 11 and 12 are in close contact with the surface along whichthe discharge is to take place, and for this reason I have arranged theelectrodes in close contact with the wall of the tube, as clearly shownin the drawings.

A most curious and striking property of the discharge is that it doesnot follow the same channels persistently, but frequently shifts fromone set or group of channels to another, thus giving the luminous veinsthe appearance of moving vabout verratically. The effect produced istherefore likened to a. rapid sequence of brilliant lightning flasheswithin the tube and presents the appearance of motion which is mosteffective in ,advertising displays in attracting attention.

The effect is thus produced `without resorting to the use of anyswitching or mechanical devices to produce the appearance of motion.

A ylighter construction of discharge-tube may be gained by means of theystructure shown in Figs. 4 and 5, wherein, 18 designates an outertransparent glass tube in which there is formed orlocated an innercentral tube 19.

,',Ihe same electrodes 11 and 12 may be used at opposite ends ofthetube, and a lead wire 13l may enter the tubeV atxonevend and be attachedto the electrode/11". Atthe opposite end, the' tube 18 may have alateral nipple 2() through which a lead wire 14 to the other electrode12 may be passed.

The filler 16 will then be confined in the space between the outerandinner tubes so that the. inner tube will displace the heavier` quartzfiller and therefore structure. Y

The manner of forming the inner and outer tubes is'of no importance.

There is a tendency with this straight wall type of inner tube for someof the discharge produce a lighter tn run along the outer wall 'of theinner tube where it cannot be readily seen, owing to the interpositionof the granules between the tubes, and I find that the effect isprevented by providing an inner tube 21, of an irregularl shape with aseries of annular enlargements 22 as shown in Figs. 6 and 7. In thisform the path along the central tube is long, due to the enlargements,and therefore the: discharge will follow the shorter path along theinner wall of the container. The distance between the inner and outertube of Figs. 4 and 5 may be made so small as to permit theinterposition of onlyone layer of granules. In thisjcase, dischargesalong the inner tube are equally as visible as those along the innerwall of the container. t

-In Fig. 8, the structures are substantially the same as those in Figs.1 and 2`witli the eX- ception that the tube 23 is of a semi-circularshane.

Having described my invention, I claim,-

1. An electric discharge device comprising a sealed transparentcontainer having a gas therein. electrodes having terminals. within thecontainer and a granular filler in the gasfilled container the granulesof which form numerous channels-between the electrodes .for

the passage of the discharge between the electrodes. n

2. An electric discharge device comprising a transparent outer containerwith gas therein. van inner displacing element in said con-A tainer,electrodes having terminals exposed infthe space between said outercontainer and the said inner element and a filler of granular insulatingmaterial in said space between said electrodes. "f'

3. An electric discharge device comprising a ,transparent containerhaving gas therein, spaced electrodes in the container and in contactwith the inner wall thereof and a granular filler in the containerbetween said electrodes said filler forming: numerous channels for thepassage of discharge between the electrodes and producing the effect ofmoving luminous veins in the container.

4.- An electric discharge device comprisingv a transparent outer tubewith a gas therein, an inner tube spaced from the outer tube, a gran-,ula'r filler in said space between the outer and inner tubes and spacedelectrodes in the outer tube. i

5. An electric discharge device comprising a transparent outer tube witha gas therein,

an inner tube spaced from the outer tube, said innertube havingenlargements at spaced intervals, spaced electrodes in the space betweenthe outer and inner tubes and a granular -filler in said space betweensaid electrodes.

In testimony whereof Iv affix inv signature.

RICHARD E. VOILRATH.

